We have studied the relation between the stability of ferromagnetism and th
e atomic volume of FCC Fe-Cu-Au alloys prepared by mechanical alloying by m
eans of X-ray diffraction, magnetization measurement and Mossbauer effect.
The atomic volume of the FCC Fe0.5Cu0.5 alloy increased almost linearly wit
h the substitution of Au atoms for Cu from original 12.09 x 10(-3) to 13.31
x 10(-3) nm(3) for 40% replacement. The Curie temperature of the alloy als
o increased in the same manner from 489 to 582 K. It is found that the incr
ease in atomic volume stabilizes the ferromagnetic state of the FCC alloys.
The values of magnetic moment of iron in Fe0.5Cu0.4Au0.1 and Fe0.5Cu0.3Au0
.2 were estimated to be 2.34 and 2.44 muB, respectively, which are larger t
han that of alpha -iron (2.22 muB). The magnetic hyperfine field of iron in
Fe0.5Cu0.4Au0.1 showed wide distribution from 22 to 38 T at 82 K, which is
probably caused by the variation of species of surrounding atoms of iron.
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